Can I replace underground condensate black pipe w copper

Alarry

Hello. I have a 1 pipe steam boiler and one of my 2 condensate lines goes underground. I replaced it in 94 when it rusted but only got 25 years out of it before it rusted/leaked again. I insulated it but I guess not good enough though much of the pipe still looks good. I was wondering if it would be acceptable to use black pipe and transition to copper below the water line and underground as installation would be much easier. If ok do I need to match the current condensate pipe size (1 1/2 inch) or can I go with 1 inch or 3/4 inch below the water line as it would be cheaper? I'm also assuming copper underground would last longer. Thanks.

KC_Jones

First question, does it have to be underground? As long as it's below the water line it's fine. If it was me I'd keep it above grade if possible.

Second, yes copper can be used for wet returns. I would not reduce the pipe size, but you could look at the system EDR and evaluate what pipe size may be appropriate which could mean a reduction.

I have copper on mine and the wet return water looks like drinking water.

Alarry

It was likely put underground when the house was built due to clearance issues when walking in the basement. If I went above grade now it would hang about 5 feet from the floor. My boiler is 3 section so I'm thinking the volume requirements for 1 of the condensate returns can't be too great.

Pumpguy

Condensate piping that must be below basement floor level is best done in an open trench using lift off steel plate for a cover. If the run is long, that could be difficult and expensive.

From what I've read, copper embedded in concrete for radiant systems was not successful, and Pex is now used. Have no personal experience in this area, so others please correct me if this is wrong. Haven't heard if this would work for condensate return piping.

There are products specifically sold to shield and insulate underground piping from corrosion and heat loss. I believe one was called Dritherm, and the other Gilsonite. You might want to look into these.

And of course, you could use a condensate pump to run the piping overhead. Most here in this site frown on the use of pumps for this application, but they are an alternative to consider.

KC_Jones

Alarry said:

It was likely put underground when the house was built due to clearance issues when walking in the basement. If I went above grade now it would hang about 5 feet from the floor. My boiler is 3 section so I'm thinking the volume requirements for 1 of the condensate returns can't be too great.

I'm not sure I understand this comment?

When I say above grade that means right at floor level keeping it below the water line. If that isn't feasible then yes they need to be buried again.

I will second the above trench ideas. I've seen pics on @gerry gill business website showing this method.

pecmsg

Copper Underground is fine, in contact with concrete no.

Black Iron rusted out in 25 years why? Is this basement wet, ground water? You might want to find out!

Alarry

Basement is always damp in the summer but no measurable water collecting anywhere. The pipe underground is 16' and the breach was in the middle of the basement floor so there was no rain water coming from an outside storm gutter or anything like that. Most of the pipe looks like it did the day I installed it so not sure why it rusted badly in 1 spot only. I didn't think heat loss was a concern for a return pipe. Neither of my 2 returns are insulated beyond the air vents. Should I insulate them?

EBEBRATT-Ed

@Alarry , use copper, keep it the same size. Use "armaflex" foam type pipe insulation with 1/2" wall thickness.......(don't use the cheap stuff the box stores sell) use that on the underground pipe only it will keep the concrete away from the copper.

Use fiberglass insulation on the above ground piping

dopey27177

Black pipe service life is 20 years above ground. Usually the pipe can last much longer.

If you transition to copper pipe make sure you wrap it with a bituminus membrane where it will come in contact with cement or concrete.

Jake

Jamie Hall

I second @KC_Jones 's puzzlement. Why can't it be right at floor level? That's the best place, assuming you can route it so it isn't a trip hazard.

Alarry

It can't be at floor level as it would be a trip hazard. If it ran close to the wall it would be ok but unfortunately it does not.

Jamie Hall

That's too bad. Pity there isn't a way to reroute it so it can go close to the wall -- since wet returns don't have to be straight.

But, if you have to run it below floor level, I myself would put it in a trench with a removable cover, so it could be inspected. If I couldn't possibly do that, I would use black iron with a suitable bituminous or epoxy coating. You can use copper, but it must be protected similarly. And I would plan on no more than a 20 year life for either one.

pecmsg

It adds a little to the job but it will keep it dry

KC_Jones

Alarry said:

It can't be at floor level as it would be a trip hazard. If it ran close to the wall it would be ok but unfortunately it does not.

Just to be clear so you fully understand your options. You can pretty much run the pipe anywhere you want. If you want to relocate it against a wall you can, it most certainly doesn't have to stay in it's current location. This is especially true of wet returns, they can even go up and down as long as they stay fully submerged. I would just be sure to use tees at any elevation change for maintenance purposes.

Typically the only issue with running at floor level is doorways.